Fix BUILD.gn files and add presubmit step

BUILD.gn

 # Copyright 2014 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import("//build/config/android/config.gni")
 import("//build/config/arm.gni")
 import("//build/config/dcheck_always_on.gni")
 import("//build/config/mips.gni")
 import("//build/config/sanitizers/sanitizers.gni")
 
@@ skipping 1754 matching lines @@
       "src/crankshaft/x64/lithium-x64.h",
       "src/debug/x64/debug-x64.cc",
       "src/full-codegen/x64/full-codegen-x64.cc",
       "src/ic/x64/access-compiler-x64.cc",
       "src/ic/x64/handler-compiler-x64.cc",
       "src/ic/x64/ic-compiler-x64.cc",
       "src/ic/x64/ic-x64.cc",
       "src/ic/x64/stub-cache-x64.cc",
       "src/regexp/x64/regexp-macro-assembler-x64.cc",
       "src/regexp/x64/regexp-macro-assembler-x64.h",
+      "src/third_party/valgrind/valgrind.h",
       "src/x64/assembler-x64-inl.h",
       "src/x64/assembler-x64.cc",
       "src/x64/assembler-x64.h",
       "src/x64/code-stubs-x64.cc",
       "src/x64/code-stubs-x64.h",
       "src/x64/codegen-x64.cc",
       "src/x64/codegen-x64.h",
       "src/x64/cpu-x64.cc",
       "src/x64/deoptimizer-x64.cc",
       "src/x64/disasm-x64.cc",
@@ skipping 996 matching lines @@
     ":fuzzer_support",
     ":lib_wasm_section_fuzzer",
     ":wasm_module_runner",
   ]
 
   configs = [ ":internal_config" ]
 }
 
 v8_fuzzer("wasm_data_section_fuzzer") {
 }